Donald H. Lambert Boston, Massachusetts Spinal Anesthesia Donald H. Lambert Boston, Massachusetts http://www.debunk-it.org

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Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Advantages of Spinal Anesthesia Technically easy Objective end-point Rapid onset Profound sensory and motor block Low potential for systemic toxicity

Disadvantages of Spinal Anesthesia Limited duration Limited sensory and motor separation “Hypotension” Potential neuro-toxicity Headache

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Indications Any operation in the lower abdomen and below

Absolute Contraindications Patient refusal Uncorrected hypovolemia Uncorrected coagulopathy Infection at site of injection Increased intracranial pressure

Relative Contraindications Some neurologic diseases Bacteremia Deformities that preclude doing an LP easily

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Positioning for the Lumbar Puncture Two choices Sitting Lateral decubitus (recumbent)

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Getting the needle in the right spot What is the object of the game of basketball? Get the ball in the hoop (Red Aurbach). What are we trying to do with spinal anesthesia? Get the needle into the CSF.

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Baricity The density of the local anesthetic solution in relation to the density of the CSF More dense than CSF hyperbaric sinks Same density as CSF isobaric stay where it is injected (relatively) Less dense than CSF hypobaric floats

Hyperbaric Isobaric Hypobaric

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Spinal Anesthesia Dosing will affect Spread Duration Quality of Anesthesia That is, the need for supplemental IV medication

The dosing in this study was 10 mg, 15 mg, and 20 mg of bupivacaine The lowest dose limited spread The lowest dose also resulted in more failures than the higher doses.

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Spinal Anesthesia Agents

Dosing Guidelines Based on the spinal canal model (and many years of doing this) Hyperbaric solutions extend into the thoracic region Isobaric solution remain in the lumbar region Hyperbaric Isobaric I give hyperbaric solutions for operations above the L1 dermatome and isobaric solutions for those below

Dosing Guidelines Hernia operations and those operations whose innervation is by nerves above L1 HYPERBARIC Those operations whose innervation is by nerves below L1 (pretty much all lower extremity operation including hip operations) ISOBARIC

CHOOSING A LOCAL ANESTHETIC FOR SPINAL ANESTHESIA BASE DECISION ON THE DURATION OF THE OPERATION

CHOOSING A LOCAL ANESTHETIC FOR SPINAL ANESTHESIA GIVE ENOUGH TO PROVIDE ADEQUATE ANESTHESIA ? CHLOROPRACAINE, ? ROPIVACAINE

Isobaric Spinal Anesthesia Epidural Bupivacaine for spinal anesthesia is an “off label use” of this agent It says right on the bottle: “Not for spinal anesthesia” What is the value or wisdom behind using that agent? It works great and I have used it since the 1980’s. I know of no reports of complications associated with using it. Litigation for the off-labeled use of a drug has not appeared in the ASA closed claims database. Who would know? Unless you wrote on your anesthesia record, “I used the bupivacaine that is not for spinal anesthesia.”

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Narcotic work here in the substantia gelatinosa Local anesthetics work here in the nerve roots

Spinal Anesthesia Addition of narcotics Fentanyl (15-25 ug lasts a few hours) Sufentanil (10 - 20 ug lasts a few hours) Morphine (100 - 200 ug lasts 12-24 hours) Side effects (increase with increasing dose) Nausea and vomiting Itching Respiratory depression

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Spinal Anesthesia Complications Cardiac arrest Hypotension Headache Nerve injury

Cardiac Arrest Still Occurring Editorial on Auroy’s study: “Spinal anesthesia appears in this study to be more dangerous than other regional anesthesia techniques.” “The risk of cardiac arrest is five- to six fold greater than with other regional anesthetic techniques ” Eisenach, James C. Regional Anesthesia: Vintage Bordeaux (and Napa Valley) Anesthesiology 1997;87:467-469

Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors Caplan, R A; et al. Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors. Anesthesiology 1988;68:5-11 Caplan, R A; et al. Injuries Associated with Regional Anesthesia in the 1980s and 1990s: A Closed Claims Analysis. Anesthesiology. 2004;101:143-152

Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors Caplan, R A; et al. Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors. Anesthesiology 1988;68:5-11

Initial Clues of Impending Arrest Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors Initial Clues of Impending Arrest Caplan, R A; et al. Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors. Anesthesiology 1988;68:5-11

Factors Predisposing to Asystole Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors Factors Predisposing to Asystole High level Loss of Cardiac Sympathetic Stimulation Unopposed Vagal Tone Decreased Venous Return Empty Left Ventricle Activation of Intracardiac Reflexes ? So-called Bezold-Jarisch Reflex ? So-called Vaso-vagal Syncope Caplan, R A; et al. Anesthesiology 1988;68:5-11 and Mackey, D C, et al. Anesthesiology 1989;70:866-868

Cardiac arrest during spinal anesthesia How can this be prevented and/or treated? Maintain venous return at all cost Use epinephrine at the first sign of cardiac arrest Keats, A. S. Anesthesia mortality--a new mechanism. Anesthesiology 1988;68:2-4.

Cardiac Arrest Associated with Anesthesia (per 10,000) * ”Regional Anesthesia”

Cardiac Arrest Associated with Anesthesia There appears to be two mechanisms for cardiac arrest during spinal anesthesia Spinal factors Vaso-depressor syncope Factors other than the spinal Blood loss Cardiac events Orthopedic manipulations

Spinal Anesthesia Complications Cardiac arrest Hypotension Headache Nerve injury

Spinal Anesthesia Complications Hypotension (happens!)

Spinal Anesthesia Complications Cardiac arrest Hypotension Headache Nerve injury

The Two Components of Spinal Headache There must have been a lumbar puncture The headache is related to posture Worst when standing or sitting Gone or improved with recumbence

Effect of Age on the Incidence of Spinal Headache Vandam and Dripps JAMA 1956;161:586-591

Effect of Needle Gauge on the Incidence of Spinal Headache Vandam and Dripps JAMA 1956;161:586-591

Spinal Anesthesia Complications Cardiac arrest Hypotension Headache Nerve injury

Nerve Injury with Spinal Anesthesia Two types Permanent Cauda equina syndrome Adhesive arachnoiditis Non-permanent Transient radicular irritation

Permanent Nerve Injury with Spinal Anesthesia Lidocaine spinal anesthesia was associated with 14.4 per 10,000 neurologic complications compared to 2.2 per 10,000 for bupivacaine spinal anesthesia. Auroy Y. et al. Major complications of regional anesthesia in France: The SOS Regional Anesthesia Hotline Service. Anesthesiology 2002; 97: 1274-80

Permanent Nerve Injury with Spinal Anesthesia In the cases [of cauda equina syndrome and paraparesis] after subarachnoid block, hyperbaric 5% lidocaine was used in eight cases, bupivacaine 0.5% in 11 cases, and in one case a mixture of both drugs was used. Moen V. et al: Anesthesiology 2004; 101: 950-9

Major Complication of Spinal Anesthesia Spinal is somewhat more dangerous in causing cardiac arrest and major nerve injury than epidural or general Epidural has a neurological injury rate similar to spinal but the injuries are different Epidural are associated with hematoma and compressive nerve injury (? owing to volume) Spinals are associated with local anesthetic toxicity

Permanent Nerve Injury with Spinal Anesthesia Neurologic injury associated with paresthesia or pain on injection is believed to be traumatic. Neurologic injury not associate with paresthesia or pain on injection is believed to be due to local anesthetic toxicity.

Nerve Injury Still Occurring Editorial on Auroy’s study: “Spinal anesthesia appears in this study to be more dangerous than other regional anesthesia techniques.” “Neurologic injury is two- to threefold greater with spinal than with other regional anesthetic techniques.” Eisenach, James C. Regional Anesthesia: Vintage Bordeaux (and Napa Valley) Anesthesiology 1997;87:467-469

Non-permanent Nerve Injury with Spinal Anesthesia Minor complications Transient neurologic symptoms (TNS) a.k.a. transient radicular irritation (TRI)

Non-permanent Nerve Injury with Spinal Anesthesia TNS/TRI Most frequent with lidocaine (10-34% incidence) More frequent with lithotomy position and knee arthroscopy VAS pain score averages 6 out of 10 Many rate the pain worse than their incision Can last up to three days Least frequent with bupivacaine

Non-permanent Nerve Injury with Spinal Anesthesia TNS/TRI The best alternative to lidocaine appears to be bupivacaine. Lasts too long Other shorter acting substitutes have not caught on. Procaine, mepivacaine, prilocaine, ropivacaine

Non-permanent Nerve Injury with Spinal Anesthesia TNS/TRI Chloroprocaine (off label) is being rediscovered as a short acting spinal anesthetic. Series of ten articles by Dan Kopacz et al. in the last year (see Anesth Analg 2004 and 2005) Comparable to lidocaine. No TNS

Non-permanent Nerve Injury with Spinal Anesthesia TNS/TRI The spinal anesthetic profile of 40 mg chloroprocaine compares favorably with the same dose of spinal lidocaine Lidocaine was associated with mild to moderate TNS in 7 of 8 subjects No subject complained of TNS with chloroprocaine Yoos JR, Kopacz DJ:. Anesth Analg 2005; 100: 566-72

Does General Anesthesia Cause Nerve Injury?

Spinal Anesthesia Advantages v. Disadvantages Indications and Contraindications Positioning Getting ready Getting the needle in the right spot Baricity Dosing What to inject Addition of a vasoconstrictor Addition of narcotics Complications (and how to avoid them)

Unanswered questions are better than unquestioned answers!

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